Birch forests from Betula litwinowii and Betula raddeana of the Northern macroslope of the Greater Caucasus with participation of Rhododendron caucasicum in the undergrowth are discussed in the article. The studies were carried out in 2017–2020 at the territory of Karachay-Cherkessia (Teberda State Natural Biosphere Reserve), Kabardino-Balkaria (Kabardino-Balkarian State High Mountain Reserve) and the Republic of Dagestan (Lak and Gunib districts, near the villages Burshi and Batsada). The characteristics of the growing conditions, analysis of the species and coenotic composition of communities are given. Birch forests with Rh. caucasicum are usually confined to the steep slopes of the northern exposure at the upper border of the forest belt, at an altitude of 1500–2800 m above sea level. The described communities can be divided into two groups depending on abundance and, consequently, influence Rh. caucasicum as an edificator. In the described communities there is a clear inverse correlation between the abundance of Rh. caucasicum with the projective cover of the grass-dwarf shrub layer. At the same time, the number of species in the grass-dwarf shrub layer doesn’t change significantly. The species composition of birch forests with the participation of Rh. caucasicum identified by us comprises 246 species of vascular plants. The herb-dwarf shrub layer is characterized by a relatively low species richness (on average, 26 species per sample plot). In these communities there are both characteristic forest species and representatives of subal-pine and, less often, alpine coenoses. Further study of communities of birch forests, which play sig-nificant water protection role, slope-holding and avalanche-barrier functions, is important for determining their current state, possible directions of changes, and assessing the need for protective measures in different regions.
Temperature sensitivity of willow dwarf shrub growth from two distinct High Arctic sites
